A right isosceles triangle of side a has charges $q, +2 q$ and $-q$ arranged on its vertices, as shown in figure.

What is the potential energy $U$ of this configuration of three charges? What is the significance of the sign of your answer?

A right isosceles triangle of side a has charges $q, +2 q$ and $-q$ arranged on its vertices, as shown in figure.

A fourth charge with charge $+3 q$ is slowly moved in from infinity to point $P$. How much work must be done in this process? What is the significance of the sign of your answer?

Find potential at point $P$ in the following cases:

Find potential at point $P$ in the following cases:

Find the value of $k$ if potential at $O$ is zero.

A rod is bent into a semi-circular arc of radius $R.$ The rod has a uniform linear charge distribution $\lambda .$ The potential at the centre of the arc, point $P$ is